Christine Payne Assistant Professor Office: MSE G026 Phone: 404-385-3125 Fax: 404-385-6057 E-mail Christine Payne Research Group Page

B.S., University of Chicago, 1998; Ph.D., Chemistry, University of California, Berkeley, 2003; NIH Postdoctoral Fellow, Harvard University, 2003-2006

DARPA Young Faculty Award, 2011; NIH Director’s New Innovator Award, 2009; ACS PROGRESS/Dreyfus Lectureship, 2008; NIH Research Scholar Development Award, 2007; NIH Ruth L. Kirschstein Postdoctoral Fellowship, 2004-2006

Research Interests

Living cells carry out countless chemical reactions regulated by a variety of environmental parameters; concentration, diffusion, redox state, pH, and active transport. The goal of research in the Payne Lab is to understand the mechanism of intracellular reactions in relation to the cellular environment. Our research focuses on two aspects of cellular regulation; spatial localization of enzymes in vesicles and diffusion within the crowded environment of the cytosol. Recent developments in a broad range of scientific disciplines including spectroscopy, cell biology, materials science, structural biology, and microscopy have created a unique opportunity to probe these questions directly.

Reaction Dynamics within a Cell. Cells control certain chemical reactions through the localization of substrates and enzymes within distinct vesicles that are actively transported through the cell. We are especially interested in the reactions that result from the interaction of substrate-containing vesicles with enzyme-containing vesicles. We are using two-color single particle tracking to address this question in standard cell lines and in a cellular model of the blood-brain barrier. In this case, motor proteins, rather than diffusion, bring together the substrate and enzymes. In the absence of this form of active transport, the interaction of substrate and enzymes is limited by diffusion in the crowded environment of the cell. We are using single particle tracking microscopy to characterize nanoparticle motion as a function of size, surface coating, and actin cytoskeleton to map the effective viscosity of the cell and understand the deviation from Stokes-Einstein behavior.

Intracellular delivery of nanoparticles. Nanoparticles have important biomedical applications ranging from the treatment of human disease with gene therapy to understanding basic cellular functions with fluorescent probes. For these applications to be fully realized it is necessary to deliver nanoparticles across the plasma membrane and into the cytosol of living cells. The Payne Lab is developing novel methods for the cytosolic delivery and targeting of nanoparticles in conjunction with the use of advanced microscopy techniques to understand the mechanisms of nanoparticle delivery.

Fluorescence microscopy in challenging environments. While recent developments in fluorescence microscopy make it possible to image many of the dynamic events that are essential to cellular function, new methods are necessary to observe the dynamics of single molecules inside living cells. Imaging within live cells is difficult as the emission from fluorescent probes competes with the autofluorescence of the cell. The Payne Lab is developing new optical techniques for quantitative cellular imaging. Optical methods of interest include nanometer-level imaging, spectroscopic single-particle tracking, and multiphoton total internal reflection microscopy.  

Recent Publications

"Imaging lysosomal enzyme activity in live cells using self-quenched substrates," W.H. Humphries and C.K. Payne, Analytical Biochemistry, 424, 178-183 (2012).

"Fluorescent coumarin thiols measure biological redox couples," K.G. Reddie, W.H. Humphries, C.P. Bain, C.K. Payne, M.L. Kemp, and N. Murthy, Organic Letters, 14, 680-683 (2012).

"Nanoparticles act as protein carriers during cellular internalization," Gerard W. Doorley and C.K. Payne, Chem. Commun., 48, 2961-2963 (2012).

"Endo-Lysosomal Vesicles Positive for Rab7 and LAMP1 Are Terminal Vesicles for the Transport of Dextran," W.H. Humphries, C.J. Szymanski, and C.K. Payne, PLoS ONE, 6, e26626 (2011).

"Single particle tracking as a method to resolve differences in highly colocalized proteins," C.J. Szymanski, W.H. Humphries, and C.K. Payne, Analyst, 136, 3527-3533 (2011).

"Cellular binding of nanoparticles in the presence of serum proteins," G.W. Doorley and C.K. Payne, Chem. Commun., 47, 466-468 (2011).

"Intracellular degradation of low-density lipoprotein probed with two-color fluorescence microscopy," W.H. Humphries IV, N.C. Fay, and C.K. Payne, Integrative Biology, 2, 536-544 (2010).

"Pyrenebutyrate leads to cellular binding, not intracellular delivery, of polyarginine quantum dots," A.E. Jablonski, T. Kawakami, A.Y. Ting, C.K. Payne, J. Phys. Chem. Lett., 1, 1312-1315 (2010).

"Imaging gene delivery with fluorescence microscopy," C.K. Payne, Nanomedicine, 2, 847-860 (2007).

"Cellular binding, motion, and internalization of synthetic gene delivery polymers," G.T. Hess, W.H. Humphries IV, N.C. Fay, and C.K. Payne, Biochim. Biophys. Acta, Mol. Cell Res., 1773, 1583-1588 (2007).

"Internalization and trafficking of cell surface proteoglycans and proteoglycan-binding ligands," C.K. Payne, S.A. Jones, C. Chen, and X. Zhuang, Traffic, 8, 389-401 (2007).

"Nanophotonic light sources for fluorescence spectroscopy and cellular imaging," O. Hayden and C.K. Payne, Ang. Chem. Int. Ed., 44, 1395-1398 (2005).